Data processing having incircuit emulation function

摘要

An improved data processor includes a high-speed memory that functions as a data cache during normal operation and as a trace memory to debug software in an in-circuit emulation mode. A register counts the number of storage location and overflows when a predetermined number is exceeded to cause an exception which transfers information off-chip from the trace memory. In one embodiment a starting address is stored and compared to a program counter of an instruction completely executed in the execution unit to begin the tracing.